[PATCH] MachineCSE: Add a target query for the LookAheadLimit heurisitic

[hfinkel at anl.gov]

REPOSITORY
  rL LLVM

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Comment at: include/llvm/Target/TargetInstrInfo.h:1242
@@ +1241,3 @@
+    // 5 is the value for this heuristic that used to be hard-coded into
+    // the MachineCSE pass.  I have no idea why 5 was choosen.
+    return 5;
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Can we just say something like, "The default lookahead is small to prevent unprofitable quadratic behavior." Next year, no one will know to whom "I" refers without a lot of work ;)

http://reviews.llvm.org/D9472

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